Abstract
Ph.D.
Female adult specimens of Lamproglena clariae attach to gill filaments of freshwater fish
of the family Clariidae, penetrate the gill tissue and consume blood. Previously, studies
have been done on the taxonomy of this parasite, but little research has been published on
biological aspects. Hence, it was the aim of this study to determine and record L.
clariae’s aspects of biology such as ecology, life cycle and pathology. The study was
conducted through both field and laboratory observations with specimens collected from
the Vaal Dam and Vaal River Barrage. A positive correlation was observed between the
host's physical dimensions and the size of the parasite, parasites from both sites preferred
the fourth gill and the median part of the gill arch for attachment. There was no
significant host gender preference by parasites. Three free living nauplius stages, four
copepodite, a cyclopoid and adult stages were recorded as life stages of this parasite.
Observations suggested that development of larval stages of L. clariae is influenced by
both photoperiod and temperatures. Furthermore low infestation success of the
experimental fish was observed. This parasite caused localised infestation as varying
degrees of swelling of gill filaments were observed only in the vicinity of its attachment
site. Histological examination revealed epithelial hyperplasia, resulting in fusion of gill
lamellae and necrosis of the host tissue in the vicinity of the parasite. No correlation
exists between the infestation intensity and fish haematocrit values. Although L. clariae
causes localized infestation, high intensity of infestation may be detrimental to the fish.
Hyperplasia of epithelial tissue resulting in fusion of lamellae would result in restriction
of oxygen passage and thus hinder the process of respiration of the host.
Prof. A. Avenant-Oldewage